Figure - available from: Aerobiologia
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Concentrations of airborne Bacterial 16S rDNA gene copies determined by qPCR analyses for different fuel/engine type and tourist buses. The number above each of the boxes refers to the number of samples taken in each kind of fuel bus
Source publication
Public bus system worldwide transports daily more than 34 million people; therefore, air quality inside buses is an important urban air pollution issue. Airborne microbiological composition and abundance was examined inside five different fuel type buses (diesel (EURO IV and EURO V), hybrid diesel (HD), compressed natural gas (CNG), hybrid natural...
Citations
Air quality inside commuter transport is an important public health issue. However, there is currently limited information on commuter exposure to the microbial fraction of airborne particles (i.e. bioaerosols) in different types of transport. Here we investigated the abundance and diversity of bioaerosols in public trains and private automobiles in the UK using molecular approaches. Overall, bacterial 16S rRNA gene abundances were significantly greater with the train (between 3.07×10^5 and 8.97×10^5 copies/m^3) compared to the car (between 4.21×10^4 and 4.78×10^5 copies/m^3) (p-value 0.019 < 0.05), with no significant differences found with train journeys throughout the day (p-value > 0.05). In terms of microbial composition, significant differences were found between the two modes of transport, for both bacterial and fungal communities. Specifically, bacteria were dominated by Proteobacteria (trains: 37 %; cars: 30 %), Firmicutes (trains: 20 %; cars: 36 %), Actinobacteria (trains: 34 %; cars: 16 %) and Bacteroidetes (trains: 6.1 %; cars: 13 %). Within the fungi, Ascomycota were predominant in the train (80 %), while the car was dominated by Basidiomycota (70 %), which may be due to the time of year sampled. Additionally, a core bacterial and fungal microbiome, including human commensals and outdoor-originating micro-organisms, alongside several taxa of human health concern were found in the air of both modes of transport. This study provides an important insight into the aerosol microbiome in transport micro-environments, which is crucial for the evaluation of commuter exposure to potential health risks.
Metagenomics is a novel genomic tool employed to accurately study the composition of microbial communities in their ecological environments, including mass transport systems. Despite the potential significance of these sites as sources of exposure, the pathogenic microbiomes in these constructed settings remain unexplored. In this study, high-throughput sequencing was utilized to identify the microbiota obtained from the Metropolitan Transport of Shanghai (MTS) during the spring and summer. A diverse range of microbiota, especially pathogens, and models for mapping diversity and environmental variables were analyzed using the metagenomic techniques. The results indicate that bacteria accounted for 95.26% of the categorized genes in the 108 aerosol samples analyzed during the spring and summer, with the remaining 4.73% attributed to eukaryotes, viruses, and archaea. We successfully identified 86 microorganisms that align with the National Microbiology Data Center's List of Pathogenic Microorganisms, uncovering unique characteristics of various species with potential health implications throughout across seasons. Additionally, the distribution and diversity of the microbiota were significantly influenced by temperature, humidity, season, and time of day. The study's findings establish a framework for investigating and evaluating potential public health risks, offering early warning of biosecurity concerns related to these built environments. They also provide a comprehensive and unbiased perspective on the characteristics of microbial communities and potential pathogens in urban metros. Environmental and public health experts will find this investigation into the pathogenic microbiomes found in aerosol samples compelling.
The measurement of airborne endotoxins is often necessary because of the inhalation of these lipopolysaccharides from most Gram-negative bacteria is known to provoke harmful effects on worker’s health including acute respiratory symptoms. Sampling on filters is one of the most widely used methods for measuring endotoxins in the air, and the present article confirms that there is a wide variety of filters used for the measurement. This article provides an expert opinion based on a mini review on the influence of the nature of the filter used on the measurement results. First, the analysis of published studies shows that the measurement of endotoxins, either at the workplace or in laboratory conditions, is carried out with different measurement protocols from one study to another, at least with regard to the filter used. Secondly, this is questioning since the equivalence of protocols in terms of measurement performance has not been fully investigated. In particular, the review of studies that have investigated the effect of the filter on the measurement of airborne endotoxins is quite contradictory, and no recent published study has provided any tangible evidence. This leads to the conclusion that the current recommendations regarding the type of filters to be used for endotoxin measurements are based on insufficient data. Thus, additional experimental studies are required. Thirdly, a detailed and argued survey of the mechanisms involved in the measurement has been carried in order to facilitate the construction of further studies. This allowed identifying the factors, including either physical or chemical properties of the filter, to be taken into account in studies on the effect of the filter on the measurement of endotoxins in the air and specifying the issues that have not yet been investigated. Finally, the results of these studies should allow a more objective orientation towards a given type of filter and could complement the recommendations of the EN14031 standard.
